McCarthy T L, Centrella M, Canalis E
Department of Medicine (Endocrine Section), Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105.
Endocrinology. 1989 Jan;124(1):301-9. doi: 10.1210/endo-124-1-301.
Insulin-like growth factors I and II (IGF-I and -II) are polypeptides secreted by skeletal cells and are considered regulators of bone formation. IGF-I and -II were studied for their effects on collagen synthesis and degradation in cultures of intact fetal rat calvariae and on type I collagen transcript levels in osteoblast-enriched (Ob) cells from fetal rat parietal bone. IGF-I and -II increased [3H]proline incorporation into type I collagen independently of their effect on cell replication. IGF-I and -II also decreased collagen degradation in calvarial cultures. Both factors had similar actions, although IGF-I stimulated collagen synthesis at 10 nM, and IGF-II at 30 nM. In Ob cells, IGF-I and -II also increased [3H]proline incorporation into type I collagen, but the effect was seen at 100 nM, and neither factor decreased collagen degradation. Slot blot analysis of IGF-I- and IGF-II-treated cells, using a rat type I collagen cDNA probe, revealed an increase in type I collagen transcripts. In conclusion, IGF-I and -II increase bone collagen synthesis and decrease collagen degradation in cultures of intact calvariae; the effect on collagen synthesis correlates with an increase in transcript levels in Ob cells.
胰岛素样生长因子I和II（IGF-I和-II）是由骨骼细胞分泌的多肽，被认为是骨形成的调节因子。研究了IGF-I和-II对完整胎鼠颅骨培养物中胶原蛋白合成和降解的影响，以及对来自胎鼠顶骨的成骨细胞富集（Ob）细胞中I型胶原蛋白转录水平的影响。IGF-I和-II增加了[3H]脯氨酸掺入I型胶原蛋白的量，且与其对细胞复制的影响无关。IGF-I和-II还减少了颅骨培养物中的胶原蛋白降解。两种因子具有相似的作用，尽管IGF-I在10 nM时刺激胶原蛋白合成，而IGF-II在30 nM时起作用。在Ob细胞中，IGF-I和-II也增加了[3H]脯氨酸掺入I型胶原蛋白的量，但这种作用在100 nM时才可见，且两种因子均未降低胶原蛋白降解。使用大鼠I型胶原蛋白cDNA探针，对经IGF-I和IGF-II处理的细胞进行狭缝印迹分析，结果显示I型胶原蛋白转录物增加。总之，IGF-I和-II在完整颅骨培养物中增加骨胶原蛋白合成并减少胶原蛋白降解；对胶原蛋白合成的影响与Ob细胞中转录水平的增加相关。
